Lost to the Ages

To start this quest you can do a few things one get a book called THE AETHERIUM WARS or you could just go straight to Arkngthamz which is located south of Dushnik Yal and thats southeast of Markarth. Upon completion of the quest you recieve the achievement of the same name.

Objectives

Reach the summit of Arkngthamz

Solve the Tonal Lock

Claim the treasure of Arkngthamz

Speak with Katria

Search for the Aetherium Shards (4/4)

Locate the Aetherium Forge

Speak with Katria

Place the Aetherium Shards

Retrieve the Aetherium Crest

Stand Clear

Find the Aetherium Forge

Shut off the Steam

Defeat the Guardians of the Forge

(optional) Shut off the Steam

Speak with Katria

(optional) Search for Crafting Materials

Use the Aetherium Forge

Walkthrough

Upon entering Arkngthamz you will begin hearing a voice saying to turn back. Rumbling and groaning from minor earth shifts will happen spilling minor dirt up from time to time as well as large chunks of rock falling from the ceiling to the water in the chasm below. When you enter the first main cavern the spirit of Katria will greet you and say how foolhardy you are to enter this place. Accept her assistance to journey deeper and you will begin Lost to the Ages as a quest proper.

Fight your way upwards through falmer and charus until you reach another large cavern where 3 locked doors and 5 tonal locks await you. If you have picked up katria's journal from her dead body in the first large chamber it gives you the first two in order that you need to hit, a scrap of paper on an adventurer in the tonal lock room gives you the 3rd. The Correct pattern is fairly easy to deduce from these clues. Bottom left, Bottom right, Top left, Top right, Center. The two side doors open and you continue on past the centurian into the vault with the first Aetherium Shard to the key to the forge.

At this point you leave Arkngthamz and venture out into the world again, the next dungeon you enter to continue this is Raldbthar. Before you leave dont forget to pick up Zephyr the unique bow from off the end of the tree where Katria fell to her death. If you have found and explored Raldbthar and have unlocked its great lift already, just skip the next paragraph and continue on.

Raldbthar is full of bandits and dwarven automatons if you havent cleared it before now, feel free to now. Further in there is a lever that leads to the Raldbthar Deep Market which is filled with falmer. Work your way past them and the traps until you reach a large room with some falmer, charus and gears on the walls that have bones stuck inside them. Free the 4 bones and dwarven scrap metal (underwater) from the gears to unlock the bridge button and fight with the centurian.

In the next room you see an entrance into Blackreach, bypass it and head down the other corridor into a small side path where Katria's ghost awaits you in front of the 2nd Aetherium Shard.

Exit through the great lift up to the surface and head north of Markarth to Deep Folk Crossing. Head up to the top of the site to see what looks to be an altar of some kind, the 3rd shard is on the backside of it.

Travel to Mzulft but dont go inside, the 4th shard is inside a Dwarven Storeroom south of the entrance to Mzulft, it is behind either one locked gate or two locked doors and depending on your lockpicking the doors may be easier. Pick up the Shard and head back outside.

The Forge is located at the Ruins of Bthalft, when you reach them Katria will ask to speak with you. After you speak with her you need to activate the Dwemer Mechanism which looks like two circular wheels with an arrow shot through them. As you finish placing them the wheels spin the arrow around and then stops. Katria speaks up that you should try taking it out. When you do the earth starts to rumble and you need to step aside quickly as a large tower shoots from the ground revealing a great lift.

Proceed down a path that lights itself for you until you reach a locked gate with two tonal locks above it, hit them both to open the gate and enter a near pristine Dwemer facility. After a lengthy set of stairs you open a door and get your first glipse of the forge itself shrouded in steam. As you shut off the steam you face your first enemies in here, wave after wave of spiders, spheres, and a large centurian named the forgemaster attack, and to top it off the steam comes back to scald you if you stay in the center of the room.

When everything lies broken on the floor Katria speaks up to you that this is the chance to use the aetherium forge and that you should have the honors. She then curses that there is no aetherium here but remembers the shards that allowed you entrance. At the forge itself you have a few options to choose from and create, when you do you complete the quest and open back up the entrance.